A typical sod harvester contains a set of internal sod stations and sod transfer mechanisms that transfer a sod roll from station to station within the sod harvester before stacking the sod rolls on a sod pallet, which is then left on the field for later pickup. Typically, the sod harvester cuts and then winds a flat sod slab into a spiral sod roll as the sod slab moves toward a discharge end of a sod elevator. The sod roll is held together by the friction between the wound layers of the sod slab and the gravitational forces acting on the sod slab. One of the drawbacks in handling such sod rolls is that the integrity of the sod roll may deteriorate as the sod harvester transfers the sod rolls within the sod harvester. In one method the sod roller orientates the cut end of the slab to inhibit unwinding of the sod roll as shown in U.S. Pat. No. 9,648,797. Another example of a method to prevent a sod roll from unwinding in a sod accumulator is shown in U.S. Pat. No. 8,813,861, which shows a topside sod roller located downstream of the sod roll mechanism and above the sod rolls on the sod accumulator. In operation the topside sod roller rolls over the top of each the sod rolls as the sod rolls lay on the accumulating conveyor in order to keep the sod rolls thereon from unwinding as the accumulating conveyor moves the sod rolls from one location to another. Unfortunately, the prior art topside roller fails to address the problem of sod roll integrity as the sod roll is transferred between stations in the sod harvester and, more specifically, to the problem of sod roll unwinding as the sod roll falls from a discharge end of one conveyor onto a lower accumulating conveyor.